Lamp cord



Jan. 29, 1935. E, H LEWIS 1,989,483

LAMP CORD Filed Feb. 27, 1932 Inventor-z Edward H. Lew i S,

H is At torneg.

Patented Jan. 29, 1935 PATENT OFFICE LAMP CORD Edward H. Lewis, Bridgeport, Conn., assignor to General Electric Company, a corporation of New York Application February 27, 1932, Serial No. 595,568

1 Claim.

My invention relates to electrical conductors and more particularly to lamp cords.

The, object of my invention is to provide an improved lamp cord which will be substantially 6 name-proof and in which the outer layer of insulation will adhere tenaciously to the other layers of insulation on the conductors.

What I consider to be novel and my invention will be better understood by reference to the following specification and appended claim when considered in connection with the accompanying drawing'.

In the drawing the single flgure is a side elevation of a parallel conductor lamp cord embodying my invention with the different layers of insulation cut away to expose other layers of insulation. 10 indicates the lamp cord generally which is composed of two parallel electrical conductors. Each conductor consists of a stranded copper` core 11 covered by a cotton wrap or winding 12 over'which is tubed a layer of rubber insulation 13. Onithis rubber insulation 13 a layer of asbestos 14 is felted. The two conductors are covered by an overall fibrous braid 15. The asbestos covering 14 is felted directly over the rubber covering 13 and adheres to the rubber covering without indenting it as is the case with a wind or braid of cotton placed over the rubber. As is well known, the asbestos is flameproof. 80 The asbestos when felted on the rubber covering adheres tenaciously to the cover right down to the point where the rubber insulation is 'stripped -rom the. end of the conductors. Thus the insulation on the conductors is made flameproof right down to the point of its connection to an electrical device. In former lamp cords the covering of cotton over the rubber would fray back from the end of the conductor from which the insulation had been stripped and thus expose the layer of rubber. Both the rubber and cotton covering might be ignited by any arc draWn within the device to which the conductor was connected. In addition the adherence of the asbestos to the rubber covering insures the required thickness of insulation right to the end of the conductor at the point at which it is connected to an electrical device. The asbestos covering 14 in addition to making the conductors flameproof also makes the lamp cord fiameproof. Although the outer braid of fibrous material may not itself be flameproof, any fiame in contact with the outer covering will not ignite it 'because the asbestos will not aid the combustion of the outer covering. In actual tests it has been found that the only point at which the outer covering has any tendency to ignite at all is at the end Where the outer covering has loose ends of the individual strands. These loose ends will ignite and burn until the flame 'reaches the portion of the coverving which closely surrounds the conductors and then it will be extinguished. Another advantage of the asbestos covering is the fact that asbestos is an ageless product and thus the lamp cord will not deteriorate in its insulating properties with age.

What I claim as new and desire to secure by Letters Patent of the United States is:

A lamp cord comprising a plurality of conductors, a cotton wrap over each conductor, a rubber covering having a relatively smooth exterior -surface over the cotton wrap, a layer of felted asbestos .over the rubber covering adhering tenaciously to the rubber covering without indenting it, and a braid of fibrous yarn over all the conductors and their insulation.

EDWARD H. LEWIS. 

